Must Have: Walt Siegl’s new Ducati Monster Leggero GTS

No dream garage would be complete without a Walt Siegl Leggero series Ducati. Builds from the New Hampshire workshop are marked by incredible craftsmanship, blistering performance and wallet-melting desirability.

A typical Walt Siegl Leggero is based on a two-valve Ducati, with a proprietary 4130 Chromoly frame. But this time around, Walt had a different configuration in mind.

“I picked a 2012 Ducati Monster 1100 as a donor,” he says, “for its engine and single-sided swing arm. My mechanic Aran Johnson had also been wanting to adapt one for a Leggero.”

This new direction meant that the ‘standard’ Leggero chassis had to be tweaked. The geometry is unchanged, but there’s a newly designed upper shock mount, additional cross bracing, and extra brackets for the electronics.

The frame’s gone on a serious diet too. “With all WSM projects, performance is paramount,” says Walt, “so I tried to come up with further possibilities to use the lightest and strongest possible components.”

That meant switching the subframe construction from steel to aluminum. The result: the frame and subframe together now weigh in at 13¾ pounds (just over six kilos).

This Leggero also has slightly more relaxed ergonomics than previous builds. Walt explains the rationale: “Since the owner of the motorcycle lives in New York City and has to spend a good amount of his riding time from red light to red light, I wanted to build a bike that has a more upright position to reduce weight on the wrists.”

Despite the more upright vibe, Walt still wanted a fairing. So he had to come up with a new design that would clear the higher bars and not look out of place—as well as a mounting system that could hold the headlight, dash and ignition.

The final design was executed in carbon. For the tank and tail, the trademark Leggero design and Kevlar weave construction was kept—with a twist.

“I wanted to show the surface quality of the WSM Kevlar parts that are normally covered by paint,” explains Walt. “So I chose a silver weave and showed it as a graphic element. It was a real chore not to appear too obvious, showy and loud.”

The WSM philosophy is to ride the line between classic design and contemporary performance. “I seem to be always trying to prove that a contemporary bike, with all its high tech components, does not necessarily have to be designed to look like a fighter jet,” says Walt, “although I don’t reject that concept.”

The best components were picked to bring the new build up to scratch. Highlights include Öhlins forks in Speedymoto triple trees, lightweight OZ Racing wheels and a sophisticated fuel injection system.

Regular WSM collaborator Bruce Meyers worked his magic with the Ducati EVO engine. Then Walt picked a full exhaust system by SC Project, tweaked to fit the new chassis. Meanwhile, Aran built a whole new wiring harness—quite a chore, considering all the modern components in play.

Leonard Lee of LWS Tuning programmed the ECU to get the best out of the engine work and the exhaust system. “Gone is the lean surge of (almost) all the factory bikes in the low RPM range,” says Walt. “Power now comes in smooth and linear from idle to red line.”

Halfway through the build, Walt realized that he was creating a whole new series. So, meet the Leggero GTS: identifiable by its single-sided swingarm, lightweight chassis and upright ergonomics.

Looks like it’s time to make space in that dream garage for yet another bike.

From Walt: Many thanks again to everybody else involved with this project—Robbie Nigl of PeachPit Racing for his talent with paint. Brian O’Neill for his unmatched welding expertise. John Harvey of FuelCel for impeccable work with composite components. And my wife and WSM assistant, Laura Carden, who guide me through every project and have to deal with my complete preoccupation 24/7.